A medical institution has a sectional radiographic apparatus installed therein for imaging a distribution of a radioactive drug. A specific construction of such a sectional radiographic apparatus will be described. A conventional sectional radiographic apparatus has a detector ring with radiation detectors arranged in an annular shape for detecting radiation. This detector ring detects a pair of radiation (pair of annihilation radiation) emitted in opposite directions from a radioactive drug in a patient (see Patent Document 1 and Patent Document 2, for example).
As a type of such sectional radiographic apparatus, there is a sectional radiographic apparatus for breast examination. This image pickup apparatus for breast examination will be described specifically. FIG. 14 is a view illustrating a conventional image pickup apparatus for breast inspection. With a conventional image pickup apparatus 51 for breast inspection, one of the breasts B of a patient M is introduced into a detector ring 62 at the time of examination. In this state, the detector ring 62 detects pairs of annihilation radiation emitted from the patient M.
The detector ring 62 determines a source of the pairs of annihilation radiation emitted from the breast B, and a distribution of the radioactive drug is generated based on this position information. Since the radioactive drug has a property to accumulate more in cancer tissue than normal tissue, breast cancer can be checked by diagnosing a distribution map of the radioactive drug.